fix(oauth-provider): fix dist declaration type errors by gustavovalverde · Pull Request #8701 · better-auth/better-auth

gustavovalverde · 2026-03-20T00:20:47Z

Summary

The oauth-provider package has 8 type errors in its emitted .d.mts declarations that are invisible during development but break external consumers. This PR fixes them and adds CI validation to prevent regressions.

Why these errors are hidden

The monorepo uses customConditions: ["dev-source"] in tsconfig.base.json, which resolves workspace imports to source .ts files instead of built dist/ output:

// tsconfig.base.json
"customConditions": ["dev-source"]

Each package exports a dev-source condition:

"dev-source": "./src/index.ts"

So pnpm typecheck (root tsc --build) resolves all cross-package imports to source — types are always consistent. But the published dist declarations have real type issues.

Scenario	What TypeScript sees	Result
Root `tsc --build`	Source `.ts` via dev-source	Passes
Package-level `tsc --noEmit`	Source with dist deps (no build mode)	8 errors
External consumer via npm	Dist `.d.mts` files	Broken types

Commit 1: Fix the 8 type errors

client-resource.ts (5 errors) — auth?.options.baseURL typed as BaseURLConfig (includes DynamicBaseURLConfig) in dist. Fix: narrow to string | undefined with a typeof check.
consent.ts (1 error) — ctx.context.postLogin doesn't exist on dist AuthContext (dynamically added at runtime). Fix: cast to Record<string, unknown>.
register.ts (1 error) — redirect_uris typed as string[] | undefined in dist, assigned to string[]. Fix: default to [].
utils/index.ts (1 error) — BetterAuthError("jwt_config", "jwt plugin not found") — second arg is a string but constructor expects { cause?: unknown }. Silently ignored at runtime. Fix: drop invalid second arg.

Commit 2: Add dist declaration CI check

Adds tsconfig.dist-check.json at the repo root that:

Clears customConditions (disables dev-source resolution)
Sets composite: false + noEmit: true
Includes all downstream package sources, excluding better-auth, core, and electron (top-level packages that can't be dist-checked against themselves due to module augmentation conflicts)

Available locally via pnpm typecheck:dist and runs in CI after the build step.

How to reproduce

pnpm build
pnpm typecheck:dist  # Should pass (0 errors with this PR)

# Without this PR's fixes:
git stash
pnpm typecheck:dist  # Shows 8 oauth-provider errors

Test plan

pnpm typecheck (root, dev-source) still passes
pnpm lint passes
pnpm typecheck:dist — 0 errors (was 8)
216/216 oauth-provider tests pass

The monorepo uses `customConditions: ["dev-source"]` in tsconfig.base.json, which resolves workspace imports to source `.ts` files during `tsc --build`. This means the root `pnpm typecheck` never validates the emitted `.d.mts` declarations from `tsdown`. When consumers import `@better-auth/oauth-provider` via the published dist output (or when typechecking from within the package), 8 type errors surface because the emitted declarations lose type narrowing that the source code relies on. Fixes: - client-resource.ts: narrow `baseURL` to `string | undefined` since `DynamicBaseURLConfig` cannot be used as a static issuer/audience - consent.ts: cast context to `Record<string, unknown>` for the dynamically-added `postLogin` property - register.ts: default `redirect_uris` to `[]` instead of `undefined` - utils/index.ts: drop invalid second string arg from BetterAuthError (constructor signature is `(message, options?)` not `(code, message)`)

vercel · 2026-03-20T00:20:54Z

@gustavovalverde is attempting to deploy a commit to the better-auth Team on Vercel.

A member of the Team first needs to authorize it.

pkg-pr-new · 2026-03-20T00:22:17Z

Open in StackBlitz

@better-auth/api-key

npm i https://pkg.pr.new/@better-auth/api-key@8701

better-auth

npm i https://pkg.pr.new/better-auth@8701

auth

npm i https://pkg.pr.new/auth@8701

@better-auth/core

npm i https://pkg.pr.new/@better-auth/core@8701

@better-auth/drizzle-adapter

npm i https://pkg.pr.new/@better-auth/drizzle-adapter@8701

@better-auth/electron

npm i https://pkg.pr.new/@better-auth/electron@8701

@better-auth/expo

npm i https://pkg.pr.new/@better-auth/expo@8701

@better-auth/i18n

npm i https://pkg.pr.new/@better-auth/i18n@8701

@better-auth/kysely-adapter

npm i https://pkg.pr.new/@better-auth/kysely-adapter@8701

@better-auth/memory-adapter

npm i https://pkg.pr.new/@better-auth/memory-adapter@8701

@better-auth/mongo-adapter

npm i https://pkg.pr.new/@better-auth/mongo-adapter@8701

@better-auth/oauth-provider

npm i https://pkg.pr.new/@better-auth/oauth-provider@8701

@better-auth/passkey

npm i https://pkg.pr.new/@better-auth/passkey@8701

@better-auth/prisma-adapter

npm i https://pkg.pr.new/@better-auth/prisma-adapter@8701

@better-auth/redis-storage

npm i https://pkg.pr.new/@better-auth/redis-storage@8701

@better-auth/scim

npm i https://pkg.pr.new/@better-auth/scim@8701

@better-auth/sso

npm i https://pkg.pr.new/@better-auth/sso@8701

@better-auth/stripe

npm i https://pkg.pr.new/@better-auth/stripe@8701

@better-auth/telemetry

npm i https://pkg.pr.new/@better-auth/telemetry@8701

@better-auth/test-utils

npm i https://pkg.pr.new/@better-auth/test-utils@8701

commit: 554d0b5

cubic-dev-ai

No issues found across 4 files

Copilot

Pull request overview

Fixes TypeScript declaration (.d.mts) type errors in the published oauth-provider package that don’t show up in monorepo development due to dev-source conditional exports, improving compatibility for external consumers importing from dist.

Changes:

Fix invalid BetterAuthError constructor usage in getJwtPlugin.
Ensure redirect_uris is always a string[] in schemaToOAuth output.
Avoid relying on non-string baseURL configs by narrowing to string | undefined in the resource client.
Avoid assigning an undeclared property on AuthContext by casting before setting postLogin.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
packages/oauth-provider/src/utils/index.ts	Removes invalid second `BetterAuthError` argument to fix emitted declaration typing.
packages/oauth-provider/src/register.ts	Defaults `redirect_uris` to `[]` to satisfy required array type in emitted declarations.
packages/oauth-provider/src/consent.ts	Casts context before setting `postLogin` to avoid dist type errors.
packages/oauth-provider/src/client-resource.ts	Narrows `auth.options.baseURL` to a static string before using as issuer/audience.

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

Add `typecheck:dist` that validates package source against workspace dependencies' dist declarations instead of source (disables the `dev-source` custom condition). This catches type errors that `pnpm typecheck` misses due to `customConditions: ["dev-source"]` resolving all imports to source `.ts` files. Excludes `better-auth`, `core`, and `electron` source from the check because their `declare module` augmentations conflict with their own dist augmentations when both are visible to the compiler. Context: see better-auth#8701 for the full explanation of the `dev-source` masking issue.

gustavovalverde requested review from Bekacru and himself65 as code owners March 20, 2026 00:20

Copilot AI review requested due to automatic review settings March 20, 2026 00:20

Copilot started reviewing on behalf of gustavovalverde March 20, 2026 00:21 View session

cubic-dev-ai bot reviewed Mar 20, 2026

View reviewed changes

Copilot AI reviewed Mar 20, 2026

View reviewed changes

himself65 approved these changes Mar 20, 2026

View reviewed changes

himself65 added this pull request to the merge queue Mar 20, 2026

Merged via the queue into better-auth:canary with commit c41fa04 Mar 20, 2026
25 of 28 checks passed

gustavovalverde mentioned this pull request Mar 20, 2026

ci: add dist declaration typecheck to CI #8702

Merged

himself65 pushed a commit that referenced this pull request Mar 20, 2026

fix(oauth-provider): fix dist declaration type errors (#8701)

138666f

himself65 mentioned this pull request Mar 20, 2026

v1.5.6 stable release #8715

Merged

himself65 pushed a commit that referenced this pull request Mar 20, 2026

fix(oauth-provider): fix dist declaration type errors (#8701)

ec79fa2

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

fix(oauth-provider): fix dist declaration type errors#8701

fix(oauth-provider): fix dist declaration type errors#8701
himself65 merged 1 commit intobetter-auth:canaryfrom
gustavovalverde:fix/oauth-provider-dist-types

gustavovalverde commented Mar 20, 2026 •

edited

Loading

Uh oh!

vercel bot commented Mar 20, 2026

Uh oh!

pkg-pr-new bot commented Mar 20, 2026

Uh oh!

cubic-dev-ai bot left a comment

Uh oh!

Copilot AI left a comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Uh oh!

Conversation

gustavovalverde commented Mar 20, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

Why these errors are hidden

Commit 1: Fix the 8 type errors

Commit 2: Add dist declaration CI check

How to reproduce

Test plan

Uh oh!

vercel bot commented Mar 20, 2026

Uh oh!

pkg-pr-new bot commented Mar 20, 2026

Uh oh!

cubic-dev-ai bot left a comment

Choose a reason for hiding this comment

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

gustavovalverde commented Mar 20, 2026 •

edited

Loading